Raced in CART for some years. Now a constructor and also runs a high performance centre for cars in Fort Collins, Colorado, as well as being heavily involved in racing safety. Bill also has a huge US Cavalry collection, after growing up in a cavalry background. Tempero was also a frequent racer in sportscars. He competed from 1978 until 1987 in a range of machinery, including Lola, March and Chevron cars in the USA and Canada, taking 5 wins, 1 of them in Can-Am and the other four in 1987, when he took the Canadian American Thundercars Championship in emphatic style in his March 85C Chevrolet.